Rock drill bit



Oct. 23, R. I. SILVOLA I ROCK DRILL BIT Filed Sept. 31954. I

Ra /"5nd 5771 010 -J' INV TOR.

United States Patent ROCK DRILL BIT Raymond I. Silvola, Hancock, Mich.,assignor of onethird to Theodore Messner and Paul W. La Bine, doingbusiness under the name and style Messner La Bine, Houghton, Mich.

Application September 2, 1954, Serial No. 453,815

1 Claim. (Cl. 255-61) The present invention relates generally to new anduseful improvements in rock drilling bits and has for its primary objectto provide, in a manner as hereinafter set forth, a device of thischaracter comprising a unique combination and arrangement of parts orelements for substantially increasing the drilling speed while at thesame time providing a tool which will have a relatively long life.

Another very important object of the invention is to provide a rockdrilling bit of the aforementioned character comprising novel means forthoroughly flushing out the broken rock as the work progresses.

Other objects of the invention are to provide a rock drilling bit whichwill be comparatively simple in construction, strong, durable, compact,highly eflicient and reliable in use and which may be manufactured atlow cost.

All of the foregoing and still further objects and advantages of theinvention will become apparent from a study of the followingspecification, taken in connection with the accompanying drawing whereinlike characters of reference designate corresponding parts throughoutthe several views, and wherein:

Figure 1 is a view in front elevation of a rock drilling bitconstruction in accordance with the present invention;

Figure 2 is a view in side elevation of the tool;

Figure 3 is a top plan view; and

Figure 4 is a vertical section, taken substantially on the line 44 ofFigure 3.

Referring now to the drawing in detail, it Will be seen that theembodiment of the invention which has been illustrated comprises a bodyof suitable metal which is designated generally by reference character5. As shown to advantage in Figure 3 of the drawing, the body 5 issubstantially oval in plan. into the body 5 from the lower end thereofis a socket 6 a major portion of which is counterbored and threaded forthe reception of a conventional drill line or string, as at 7.

Formed integrally with the upper or forward end of the body 5 is acentrally located chisel-type pilot 8 comprising a substantially taperedupper end portion 9. Located in back of the pilot 8 is a pair ofsubstantially concave initial breakers 10, the purpose of which will bepresently set forth. The breakers 10, which are integral with the body5, comprise substantially V-shaped outer face portions providing pointsor angles 11. Also formed Extending longitudinally 2,767,958 FatentedOct. 23, 1956 integrally with the body 5 and located in back of and onopposite sides of the breakers 10 is a pair of substantially similarfinal breakers 12. The breakers 12 also include angular outer faceportions provided with points or angles 13.

The breakers 10 and 12 are formed to provide substantially volutechannels 14 for the reception of the broken rock. Water passages 15 fromthe socket 6 communicate with the channels 14.

It is thought that from a consideration of the foregoing the operationof the bit will be readily apparent to those skilled in the art.Briefly, as indicated by the arrow in Figure 3 of the drawing, the bitis rotated in a counterclockwise direction. When in operation, thechisel 8 pilots the hole and guides the direction of the tool. Thebreakers 10 enlarge the hole made by the chisel pilot 8, said breakerscrushing the rock inwardly toward the center of the hole. Then, thefunction of the breakers 12 is to enlarge the hole to its ultimatediameter, said breakers 12 also crushing the rock inwardly toward thecenter of the hole. The free ends of the breakers 10 and 12 are flat andconstitute cutting faces and the angles 11 and 13 provide cutting edgeswhich keep the bit rotating freely by cutting away the rock not removedby said cutting faces. The crushed rock enters the channels 14 and isflushed away by water from the string 7 flowing through the passages 15.The construction and arrangement is such as to substantially eliminategauge wear while at the same time maintaining maximum drilling speed andincreasing the life of the bit.

It is believed that the many advantages of a rock drilling bitconstructed in accordance with the present invention will be readilyunderstood and although a preferred embodiment of the tool is asillustrated and described, it is to be understood that changes in thedetails of construction may be resorted to which will fall within thescope of the invention as claimed.

What is claimed as new is as follows:

A rock drilling bit comprising: a body of substantially ovalcross-section for mounting longitudinally on one end of a drill string,a centrally located chisel-type pilot on the forward end of the body, apair of breakers on the small diameter of the body rearwardly of thepilot, and a pair of breakers on the large diameter of the bodyrearwardly of the first-named breakers, said first and second-namedbreakers defining substantially volute channels for the reception ofcuttings, said body having water passages therein communicating with thechannels for flushing away the cuttings, all of said breakers includingflat free ends constituting cutting faces and further comprisinglongitudinal angles on the outer surfaces thereof providing cuttingedges.

References Cited in the file of this patent UNITED STATES PATENTS878,145 Middleton Feb. 4, 1908 1,387,733 Midgett Aug. 16, 1921 1,809,351Oliver June 9, 1931 2,262,001 Hokanson Nov. 11, 1941 2,532,783 PhippsDec. 5, 1950

